Problem: SDE 3.x for Informix needs Client SDK 2.10
Solution or Workaround
SDE 3.0.2.x for Informix requires the use of Informix ClientSDK version 2.10. SDE will not work properly with later versions of the Informix ClientSDK. (On Unix systems, you can determine which version of the ClientSDK you are running by using the Informix command "check_version csdk".)
ESRI has been given permission by Informix to distribute this software package. If you cannot get a copy of the ClientSDK from Informix directly and if you have ESRI DSG support, please contact the DSG for a copy of Informix ClientSDK version 2.10.
You should install the Informix ClientSDK version 2.10 using the same serial number and key that they were given by Informix for the ClientSDK.
Note: This applies only to SDE 3.0.2.x for Informix version 9.14 and 9.20.